Spectrally sensitized silver halide photographic emulsion

ABSTRACT

A SPECTRALLY SENSITIZED SILVER HALIDE PHOTOGRAPHIC EMULSION, AND MORE PARTICULARLY A SILVER HALIDE PHOTOGRAPHIC EMULSION SUPERSENSITIZED BY THE COMBINED USE OF AT LEAST TWO SENSITIZING DYES RESULTING IN A HIGH RED SENSITIVITY.

Oct. 9, 1973 KEISUKE SKIBA ET'AL 3,764,340

SPECTRALLY SENSITIZED SILVER HALIDE PHOTOGRAPHIC EMULSION Filed Sept. 24, 1971 FIGI WAVE LENGTH (xlOnm) 44 4s 52 5s 60, s4 68 72 7e WAVE LENGTH (X10 nm) 44 48 52 5s so 64 as 72 76 WAVE LENGTH (xlOnm) 7 gay I '7 WAVE LENGTH (xl0nm) United States Patent O 3,764,340 SPECTRALLY SENSITIZED SILVER HALIDE PHOTOGRAPHIC EMULSION Keisuke Shiba, Haruo Takei, Akira Sato, and Tadashi Ikeda, Kanagawa, Japan, assignors to Fuji Photo Film Co., Ltd., Kanagawa, Japan Filed Sept. 24, 1971, Ser. No. 183,592 Claims priority, application Japan, Sept. 24, 1970, 45/ 83,656 Int. Cl. G03c 1/14 US. Cl. 96-124 6 Claims ABSTRACT OF THE DISCLOSURE A spectrally sensitized silver halide photographic emulsion, and more particularly a silver halide photographic emulsion supersensitized by the combined use of at least two sensitizing dyes resulting in a high red sensitivity.

FIELD OF THE INVENTION This invention relates to a spectrally sensitized silver halide photographic emulsion, and more particularly to a silver halide photographic emulsion which is supersensitized by the combined use of at least two sensitizing dyes resulting in a high red sensitivity.

BACKGROUND OF THE INVENTION (1) Prior art Photographic light-sensitive materials which are used conventionally are required to have spectral sensitivity distribution corresponding to the photographing purpose. However, for the manufacture of the sensitive material, it is difficult to develop a combination of sensitizing dyes which are in the supersensitization relation to each other and which has a small inherent desensitization, i.e. a low desensitization in the wavelength region inherent to silver halide grains.

(2) Objects of the invention An object of this invention is to provide a silver halide photographic emulsion having a high red sensitivity within the spectrally sensitized wavelength region of 620-685 11m. and a small inherent desensitization by the combined use of two different types of sensitizing dyes. In particular, it aims at the improved red sensitivity of blackwhite sensitive material having a sensitive maximum in the vicinity of 630 nm. and the improved spectral sensitivity of black-White sensitive material having a sensitive maximum in a longer wavelength region, i.e. in the region of 640680 nm.

Other objects of this invention will be apparent to those skilled in the art as the description of this invention proceeds.

DESCRIPTION OF THE INVENTION This invention is the combined use of sensitizing dyes of the following general Formulas I and II in a silver halide photographic emulsion:

wherein R represents a lower alkyl group, e.g., methyl, ethyl, propyl, etc., alkenyl, e.g., vinyl, methyl, etc.; R represents a sulfoalkyl group, e.g., 'y-sulfopropyl, -sulfobutyl, fi-sulfobutyl, etc.; A represents a lower alkyl group, e.g., methyl, ethyl, etc., or an aryl group, e.g., phenyl, p-methoxyphenyl; Z represents nonmetallic atoms re- 3,764,340 Patented Oct. 9, 1973 wherein P and Q represent hydrogen atoms or lower alkyl groups or an atomic group capable of being connected to each other to form a heterocyclic ring; X represents an anion, e.g., chloride, bromide, iodide, p-toluene sulfonate ion, etc., which are used generally in the field of sensitizing dyes, n is 0 or 1 and n=0 for intermolecular salt;

,Z; A2 Z4- -cH= J-0H= -1 N- 1&3 (Xz-)m ill (II) wherein R and R each represents a lower alkyl group, e.g., methyl, ethyl, propyl, 'y-sulfopropyl, 'y-sulfobutyl, fi-sulfobutyl, fi-carboxybutyl, etc.; A represents a lower alkyl group, e.g., methyl, ethyl, etc., or an aryl group, e.g., phenyl; Z and 2,, each represents nonmetallic atoms required to complete a benzothiazole, benzoselenazole or ,B-naphth'othiazole nucleus, which may be substituted by a halogen atom, e.g., chlorine, bromine atom, etc., a lower alkyl group, e.g., methyl, ethyl, etc., an alkoxyl group, e.g., methoxy, ethoxy, etc., a hydroxyl group, carboxyl group, alkoxycarbonyl group, e.g., methoxycarbonyl, ethoxycarbonyl, etc., and phenyl group, etc.; X; represents an anion, e.g., chloride, bromide, iodide, p-toluene sulfonate ion, etc., which are used generally in the field of sensitizing dyes; m is 0 0r 1 and m=0 for the intermolecular salt.

The cyanine dyes of the general Formula I have a sensitized maximum peak in the range of 620-650 nm. and, compared with the sensitizing dyes of the general Formula II, a very small red sensitivity. Many cyanine dyes of the general Formula II have a sharp J-band and a high red sensitivity. It has been found that the combined use of said sensitizing dyes (I) and (II) having such features improves the red sensitivity of said sensitizing dye of (II), resulting in a silver halide photographic emulsion having a very small inherent densensitization. Above all, the combination of said sensitizng dye of (I) and mesomethylthiacarbocyanine among said sensitizng dye (II) is suitable to a black-white sensitive material having a sensitized maximum peak in the vicinity of 630 nm. and shows such eifect that has not been found in the previous art, said effect extending gradually the spectral sensitization region to the longer wavelength without a large shift of sensitive maximum peak. The combination use of a sensitizing dye of the general Formula I and a symmetrical fi-naphthothiacarbocyanine of the general Formula II has a peculiar effect: that is, the sensitized maximum peak may be selected voluntarily in the region of 620- 680 nm. and the spectral sensitivity can be highly increased to maintain the red sensitivty at a high level. Said effect is not affected by using at the same time another sensitizer for improving the green sensitivity (for example, 2,2'-cyanine, thia-2-cyanine, etc.) or sensitizers having other spectral sensitization region.

The FIGS. 14 show the sensitivities of the dyes described herein when compared with various control samples. A fuller understanding of the drawings can be had by referring to Table 2 and the specific examples reported therein.

The embodiment of sensitizing dyes used in this invention are mentioned as follows, but said sensitizing dyes used in this invention are not restricted to these examples.

Dyel S S 2: 5 0H-e=0H 01 O-N N ii cH,

Dye D Dye E Dye F Dye G Dye H Dye I DyeK I CH: O

Dye L The sensitizing dyes of the general Formulas I and II, which are used in this invention, can be synthesized by a known method. For example, by reference to U.S. Pat. No. 2,503,776 and German Pat. Nos. 929,080 asd 1,072,- 765, those skilled in the art can synthesize them readily.

Typical syntheses of new sensitizing dyes of the general Formula I are described as follows:

Synthesis (i): Dye (I)l 3.0 g. of 5-chloro-3-propyl-2-thiopropionylmethylenebenzothiazoline and 4.5 ml. of methyl-p-toluene sulfonate were heated at C. for one hour and, after cooling, treated with ethyl ether to remove the unreacted material. 3.6 g. of anhydro-5-N,N-dimethylcarbamoyl-3-(' sulfopropyl)-2-methylbenzothiazolium hydroxide, 400 ml. of ethanol and 5 ml. of triethylamine were added and heated for 3 hours under reflux and the solvent was then removed. The remainder was treated with ether and then with a mixed solvent of ethanol/acetone thoroughly to yield coarse crystals, which were recrystallized from a mixed solvent of isopropanol/ethanol to yield 1.7 g. of dye. M.P. 270.5 C.;

lated (percent): C, 55.85; H, 5.36; N, 6.97. Found (percent): C, 55.67; H, 5.31; N, 6.97.

Synthesis (ii): Dye (I)2 1 g. of 5-chloro-3-allyl-2-thiopropionylmethylenebenzothiazoline and 1.5 ml. of methyl-p-toluene sulfonate were heated at C. for 1.5 hours and the unreacted solid was then washed with ether, 1 g. of anhydro-S-benzoyl- 3-(' -sulfopropyl)-2-methylthiazolium hydroxide, 200 ml. of ethanol and 1.5 ml. of triethylamine were then added and heated for 2.5 hours under refiux. The solvent was removed and the remainder was treated with ether and then with acetone thoroughly to yield coarse crystals, which were recrystallized from a mixed solvent of ethanol/ methanol to yield 650 mg. of dye. M.P. 286 C.;

kfifg 558 nm.

Analysis for C32H29N2S304C]. Calculated (percent): C, 60.25; H, 4.59; N, 4.39. Found (percent): C, 59.83; H, 4.69; N, 4.29.

Synthesis (iii): Dye (I)7 1 g. of 5-chloro-3-ethyl-2-thioanisoylrnethylenebenzothiazoline and 1.5 ml. of methyl-p-toluene sulfonate were reacted at 115 C. for 2 hours with heating and the reaction mixture was then washed with ether. 1 g. of anhydro-5-benzoyl-3-('y-sulfopropyl)-2-methylbenzothiazolium hydroxide, 200 ml. of ethanol and 2 ml. of triethylamine were then added and heated for 3 hours under reflux. After completion of the reaction, the solvent was removed and the remainder was washed with ether and then with a mixed solvent of ethanol/ acetone to yield coarse crystals, which were recrystallized from a mixed solvent of ethanol/ methanol/chloroform to yield 800 mg. of dye crystal. M.P. above 308 C.;

lated (percent): C, 61.48; H, 4.44; N, 3.98. Found (percent): C, 61.49; H, 4.55; N, 3.85.

Synthesis (iv): Dye (I)10 1 g. of S-methyl-3-ethyl-2-thiopropionylmethylenebenzothiazoline and 1.5 ml. of methyl-p-toluene sulfonate were reacted at 110 C. for 2 hours with heating and then washed with ether. To the remainder was added 1.2 g. of anhydro-S-ethylcarbamoyl 3 (y-sulfopropyD-Z-methylbenzothjazolium hydroxide, ml. of ethanol and 4 ml. of triethylamine and the admixture was heated for 3.5 hours under reflux. The solvent was then removed and the remainder washed with ether and then with ethanol/ ether to yield coarse crystals, which were washed with acetone and recrystallized twice from a mixed solvent of ethanol/isopropanol to yield 550 mg. of dye. M.P. above 300 C.;

Analysis for C23H33N3S304 lated (percent): C, 58.75; H, 5.81; N, 7.34. Found (percent): C, 58.52; H, 5.80; N, 6.95.

Synthesis (v): Dye (I)l4 0.85 g. of S-chloro-3ethyl-Z-thiopropionylmethyleneibenzoselenazoline and 1.5 ml. of methyl-p-toluene sulfonate were reacted at 110 C. for 1.5 hours on an oil bath. After cooling, the reacted solid was washed with ether, 1.25 g. of anhydro--morpholinocarbonyl-3-('y-sulfopropyl)-2-methylbenzothiazolium hydroxide were added to the solid and reacted for one hour on an oil bath with heating under reflux in 130 ml. of ethanol and 3 ml. of triethylamine. Thereafter, the solvent was distilled off and the remainder was treated first with ethanol/ ether and then with acetone to yield coarse crystals, which were recrystallized from a mixed solvent of ethanol/isopropanol to yield 170 mg. of dye. M1. 261 0.;

M22 563 um.

Analysis for C H N S SeO Cl (M.W.-=679.1).- Calculated (percent): C, 51.27; H, 4.74; N, 6.18. 'Found (percent): C, 51.30; H, 4.78; N, 6.09.

Other sensitizing dyes according to this invention can be similarly synthesized.

The spectral sensitization process according to this invention is effective for the spectral sensitization of gelatin silver halide photographic emulsion. It can also sensitize sufficiently an emulsion containing hydrophilic colloid other than gelatin, e.g., agar collodion, watersoluble cellulose derivatives, polyvinyl alcohol or other synthetic or natural hydrophilic resins. For the photographic emulsion used in this invention, a mixed silver halide emulsion such as silver iodobromide, chloroiodobromide, etc., are suitable.

For the preparation of spectrally sensitized photographic emulsion according to this invention, it is possible to add said sensitizing dye of (I) and (II) to a photographic emulsion in a common manner. In practice, it is convenient to add the dyes as a solution in a suitable solvent such as methanol, ethanol, etc., to the emulsion.

The sensitizing dyes (I) and (II) to be contained in the emulsion are used in an amount of 10- to 10- mol/mol of silver halide respectively and the molar ratio of both dyes may be varied within a wide range of from 9:1 to 1:9 corresponding to the etfect desired. The photographic emulsion according to this invention can be applied further with the hyperand other super-sensitization. In the preparation of the photographic emulsion according to this invention, additives which are generally used, for example, chemical sensitizer, stabilizer, toner, hardener, surface active agent, antifoggant, plasticizer, development accelerator, color developer and fluorescent brightening agent can be contained in the emulsion in a common manner. J

The photographic emulsion according to this invention can be coated on a suitable base, for example, glass, films of cellulose derivatives, films of synthetic resins, baryta paper or resin-coated paper in a common manner.

Examples are described as follows:

Single sensitizing dye of (I) and (II) used in this invention each was added to a silver iodobromide emulsion (AgI:AgBr7:93 in mol percent) to prepare silver halide photographic emulsions. On the other hand, silver halide photographic emulsions containing the combination of said sensitizing dyes of (I) and (II) used in this invention were prepared. These emulsions were coated respectively on a cellulose triacetate film base, dried, then exposed through a yellow filter (a filter transmitting rays of longer wavelength than 580 nm.) and a blue filter (a filter transmitting rays of 400-490 nm. and having a maximum transmission at 450 nm.) to a daylight of 64 luxes (corresponding to 5,400 K.) and developed. As the liquid developer, one having the composition shown in Table 1 was used. 1

Water to make 1 l.

The relative yellow sensitivity, relative red sensitivity and inherent desensitization to the original emulsion in the single addition of said sensitizing dyes (I) and (II) as well as in the combined use of said sensitizing dyes (I) and (II) are shown in Table 2.

TABLE 2 Amount Amount Relative Relative of sensiqt sensisensitized yellow red Inherent Example Dye tizing dye Dye tizing dye aximum sensisensisensi. ExperimentNo. No. No. added N0. added Emulsion (nm.) tivlty tivity tivity Reform- J 0.5 AgBr/I 685 62 77 9s FIG.1 1 I 1 A Br/I iii) 96 FIG. 1%2;

0 90 FIG. 1 686 135 185 (a) l a? a 32 40 I00 FIG.4 1 1 628 74 36 90 0) 630 S5 57 85 630 82 57 83 FIG. 2 (4) 630 54 64 6204540 240 225 so FIG.2(5)

630 280 280 90 FIG. 2 (6) 680 300 310 85 FIG. 2 (7) 6204360 230 280 94 620-670 300 290 6 330 3&5 88

TABLE 2.-Contlnued Amount Amount Relative Relative of sensiof sensisensitized yellow re Inherent Example Dye tizing dye Dye tizing dye maximum senslsensisensi- Experiment No. No. No. added No. added Emulsion (nm.) tivity tlvity tivity Reterto- 610 35 22 '63 625 25 55 I 1 520 110 110 66 J' 2 62B 142 142 66 J 4 620-680 141 142 60 19 21 12 1 o e AgBr/I e32 160 85 7s 12 2 C 6 AgBr/I 632 165 85 75 f E 6 AgBr/I 646 1410 125 4,5

l 22 15 2 E 6 AgBr/I 646 152 130 66 23 15 1 B 1 AgBr/I 632 146 110 87 21 15 2 B 1 AgBr/I e32 144 110 87 656 110 110 94 see 112 110 92 1 10- moi/kg. emulsion.

The yellow and red sensitivity are each shown as the relative sensitivity to the sensitivity 100 of said sensitiziug dye H which is exposed in an amount of 4X16- mol/kg. emulsion through the yellow and red filter as mentioned above and the inherent sensitivity is shown as the relative sensitivity to the sensitivity 100 of original emulsion which is exposed through the blue filter.

As can be seen from Table 2, the combined use of said sensitizing dyes (I) and (11) provides a much higher spectral sensitization than in the single use of each sensitizing dye.

As shown in Table 2 and Examples 3, 4, 11 and 12, the effect of the combination of said sensitizing dyes (I) and (II) is not injured by the further addition of known green sensitizing dye thereto, i.e. the combined use of green sensitizing dye 16 or 17 with the combination of said sensitizing dyes (I) and (II).

The green sensitizing dyes which may be used in combination with said sensitizing dye of (I) and (II) used in this invention are those having the follownig chemical structures, but they are not restricted only to these sensitizing dyes.

GREEN SENSITIZING DYE What is claimed is:

1. A silver halide photographic emulsion containing the supersensitizing combination of at least one of sensitizing dyes of the general Formula I and at least one of sensitizing dyes of the general Formula II:

wherein R represents a lower alkyl or alkenyl group, R represents a sulfoalkyl group, A; represents a lower alkyl, or aryl group, Z represents a n'on'rnetallic atom required to complete a benzothiazole, benzoselenazole or B-naphthothiazole nucleus, Z represents a sulfur or selenium atom, B represents a phenyl, or

group, wherein P and Q each represents a hydrogen atom or a lower alkyl group or an atomic group capable of being connected to form a morpholine ring, X represents an anion, n is 0 or 1, n being 0 for the intermolecular salt;

1L4 (11) wherein R and R each represents a lower alkyl group,

A represents a lower alkyl or aryl group, Z and Z each represents a nonmetallic atom required to complete a' benzothiazole, benzoselenazole or B-naphthothiazle nucleus, X represents an anion, m is 0 or 1, m being 0 for the intermolecular salt.

2. A silver halide photographic emulsion as claimed in claim 1 wherein the sensitizing dye of the general Formula II is a mesomethylthiaoarbocyanine.

3. A silver halide photographic emulsion as claimed in claim 1 wherein the sensitizing dye oi the general Formula 11 is a symmetrical fl-naphthothiacarb ocyanine.

and the sensitizing dye of the general Formula II is a member selected from the group consisting of:

Dye

Anionic mi 6 ((JHDaSOr 132KB 30 6. A photographic light-sensitive material compi'ising a layer containing the photographic emulsion as claimed in claim 1.

References Cited 35 UNITED STATES'PATEN'TS" 2,521,705 9/1950 Firestine" 9 6-137 3,468,661 9/ 1969 Libeer et a1 96-437 3,681,080 8/1972 Nakazawa et a1 96124 40 I. TRAVIS BROWN, Primary Examiner 

